Compound, resin, resist composition and method for producing resist pattern

ABSTRACT

A compound of the present invention is represented by the formula (A); 
     
       
         
         
             
             
         
       
         
         
           
             wherein R 1  represents a hydrogen atom or a C 1  to C 6  alkyl group; Z 1  represents a single bond, —CO—O—* or —CO—O—(CH 2 ) k —CO—O—*; Z 2  represents a single bond, *—O—CO—, *—CO—O—, *—O—(CH 2 ) k —CO—, *—CO—(CH 2 ) k —O—, *—O—(CH 2 ) k —CO—O—, *—O—CO—(CH 2 ) k —O— or *—O—CO—(CH 2 ) k —O—CO—; k represents an integer of 1 to 6; * represents a binding position to W; W represents a C 4  to C 36  (n+1) valent alicyclic hydrocarbon group or a C 6  to C 18  (n+1) valent aromatic hydrocarbon group, one or more hydrogen atoms contained in the alicyclic hydrocarbon group and the aromatic hydrocarbon group may be replaced by a halogen atom, a C 1  to C 12  alkyl group, a C 1  to C 12  alkoxy group, a C 2  to C 4  acyl group or —OR 10 ; R 10  represents a hydrogen atom or a group represented by the formula (R 2 -2); R 2  represents a hydrogen atom, a group represented by the formula (R 2 -1) or (R 2 -2); n represents an integer of 1 to 3; R 4 , R 5  and R 6  independently represent a C 1  to C 12  hydrocarbon group; R 7  and R 8  independently represent a hydrogen atom or a C 1  to C 12  hydrocarbon group; R 9  represents a C 1  to C 14  hydrocarbon group.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a compound, a resin, a resistcomposition and a method for producing a resist pattern.

2. Background Information

Compounds, 2-ethyl-2-adamanthyl methacrylate and p-hydroxystyrene,resins having structural units derived therefrom and resist compositionscontain these resin are described in Patent document, JP2003-107708-A.

SUMMARY OF THE INVENTION

The present invention provides following inventions of <1> to <10>.

<1> A compound represented by the formula (A);

wherein R¹ represents a hydrogen atom or a C₁ to C₆ alkyl group;

Z¹ represents a single bond, —CO—O—* or —CO—O—(CH₂)_(k)—CO—O—*;

Z² represents a single bond, *—O—CO—, *—CO—O—, *—O—(CH₂)_(k)—CO—,*—CO—(CH₂)_(k)—O—, *—O—(CH₂)_(k)—CO—O—, *—O—CO—(CH₂)_(k)—O— or*—O—CO—(CH₂)_(k)—O—CO—;

k represents an integer of 1 to 6;

* represents a binding position to W;

W represents a C₄ to C₃₆ (n+1) valent alicyclic hydrocarbon group or aC₆ to C₁₈ (n+1) valent aromatic hydrocarbon group, one or more hydrogenatoms contained in the alicyclic hydrocarbon group and the aromatichydrocarbon group may be replaced by a halogen atom, a C₁ to C₁₂ alkylgroup, a C₁ to C₁₂ alkoxy group, a C₂ to C₄ acyl group or —OR¹⁰;

R¹⁰ represents a hydrogen atom or a group represented by the formula(R²-2);

R² represents a hydrogen atom, a group represented by the formula (R²-1)or a group represented by the formula (R²-2);

n represents an integer of 1 to 3;

wherein R⁴, R⁵ and R⁶ independently represent a C₁ to C₁₂ hydrocarbongroup;

wherein R⁷ and R⁸ independently represent a hydrogen atom or a C₁ to C₁₂hydrocarbon group;

R⁹ represents a C₁ to C₁₄ hydrocarbon group.

<2> The compound according to <1>, wherein the compound represented bythe formula (A) is a compound represented by the formula (A1);

wherein R¹, R², R¹⁰, Z¹, Z² and n represent the same meaning as definedabove.

p represents an integer of 0 to 3, provided that n+p is an integer of 1to 3.

<3> The compound according to <1> or <2>, wherein the Z¹ is —CO—O—*.

<4> The compound according to any one of <1> to <3>, wherein the Z² is*—O—(CH₂)_(k)—CO— or *—O—CO—(CH₂)_(k)—O—CO—, wherein k represents thesame meaning as defined above.

<5> The compound according to any one of <1> to <4>, wherein the nrepresents 1.

<6> A resin comprising a structural unit derived from the compound anyone of <1> to <5>.

<7> The resin according to <6>, which further comprising an acid-labilegroup, and being insoluble or poorly soluble in aqueous alkali solutionbut becoming soluble in aqueous alkali solution by the action of acid.

<8> A resist composition comprising a resin according to <6> or <7>, andan acid generator.

<9> The resist composition according to <8>, which further comprises abasic compound.

<10> A method for producing a resist pattern comprising steps of;

(1) applying the resist composition of the present invention onto asubstrate;

(2) drying the applied composition to form a composition layer;

(3) exposing to the composition layer using a exposure device;

(4) baking the exposed composition layer and,

(5) developing the baked composition layer using a developing apparatus.

According to the resin and the resist composition of the presentinvention, it is possible to achieve satisfactory pattern line edgeroughness in the pattern formed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

“(meth)acrylic monomer” means at least one monomer having a structure of“CH₂═CH—CO—” or “CH₂═C(CH₃)—CO—”, as well as “(meth)acrylate” and“(meth)acrylic acid” mean “at least one acrylate or methacrylate” and“at least one acrylic acid or methacrylic acid,” respectively.

A compound of the present invention is a compound represented by theformula (A);

wherein R¹ represents a hydrogen atom or a C₁ to C₆ alkyl group;

Z¹ represents a single bond, —CO—O—* or —CO—O—(CH₂)_(k)—CO—O—*;

Z² represents a single bond, *—O—CO—, *—CO—O—, *—O—(CH₂)_(k)—CO—,*—CO—(CH₂)_(k)—O—, *—O—(CH₂)_(k)—CO—O—, *—O—CO—(CH₂)_(k)—O— or*—O—CO—(CH₂)_(k)—O—CO—;

k represents an integer of 1 to 6;

* represents a binding position to W;

W represents a C₄ to C₃₆ (n+1) valent alicyclic hydrocarbon group or aC₆ to C₁₈ (n+1) valent aromatic hydrocarbon group, one or more hydrogenatoms contained in the alicyclic hydrocarbon group and the aromatichydrocarbon group may be replaced by a halogen atom, a C₁ to C₁₂ alkylgroup, a C₁ to C₁₂ alkoxy group, a C₂ to C₄ acyl group or —OR¹⁰;

R¹⁰ represents a hydrogen atom or a group represented by the formula(R²-2);

R² represents a hydrogen atom, a group represented by the formula (R²-1)or a group represented by the formula (R²-2);

n represents an integer of 1 to 3;

wherein R⁴, R⁵ and R⁶ independently represent a C₁ to C₁₂ hydrocarbongroup;

wherein R⁷ and R⁸ independently represent a hydrogen atom or a C₁ to C₁₂hydrocarbon group;

R⁹ represents a C₁ to C₁₄ hydrocarbon group.

Examples of the alkyl group include methyl, ethyl, n-propyl, iso-propyl,n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, heptyl, 2-ethylhexyl,octyl, nonyl, decyl, undecyl, and dodecyl groups.

Examples of the alicyclic hydrocarbon group include a monovalentalicyclic hydrocarbon group such as cycloalkyl group such ascyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,cyclooctyl, cyclononyl, and cyclodecyl groups, norbornyl group,1-adamantyl group, 2-adamantly) group, isobornyl group, and a divalentclicyclic hydrocarbon group such as a cycloalkylene group such ascyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene,cycloheptylene, cyclooctylene, cyclononylene, and cyclodecylene groups,norbornylene group, adamantylene group, isobornylene group.

Examples of the aromatic hydrocarbon groups include a monovalentaromatic hydrocarbon group such as an aryl group such as phenyl,naphthyl and anthryl groups, and a divalent aromatic hydrocarbon groupsuch as phenylene, naphthylene and anthrylene groups.

Examples of the halogen atom include fluorine, chlorine, bromine andiodine atoms.

Examples of the alkoxy group include methoxy, ethoxy, n-propoxy,iso-propoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, n-hextoxy,heptoxy, octoxy, 2-ethylhexyloxy, nonyloxy, decyloxy, undecyloxy anddodecyloxy groups.

Examples of the acyl group include acetyl, propionyl and butyryl groups.

The hydrocarbon group may be any of a saturated and unsaturatedhydrocarbon groups, and any of an alkyl, monovalent alicyclic andmonovalent aromatic hydrocarbon groups. Also, the hydrocarbon group mayinclude a group formed by combining any of the above-mentioned groupssuch as aralkyl and alkyl-aryl groups.

The unsaturated hydrocarbon group may include an alkenyl (such as vinyland allyl groups), and alkynyl (such as ethynyl group) groups.

Examples of the aralkyl group include, for example, benzyl andnaphthylmethyl groups.

In the compound represented by the formula (A), particularly R¹ ispreferably a hydrogen atom or methyl group.

Z¹ is preferably a single bond or —CO—O—*, wherein * represents abinding position to W.

Z² is preferably *—O—CO—, *—CO—O—, *—O—(CH₂)_(k)—CO—,*—O—(CH₂)_(k)—CO—O— or *—O—CO—(CH₂)_(k)—O—CO—, and more preferably*—O—(CH₂)_(k)—CO— or *—O—CO—(CH₂)_(k)—O—CO—, among these, more preferredare those in which k is 1.

W is preferably a group represented by the formula (W-1);

wherein R¹⁰ represents a hydrogen atom, a group represented by theformula (R²-1) or a group represented by the formula (R²-2);

n represents the same meaning as defined above;

p represents an integer of 0 to 3, provided that n+p is an integer of 1to 3;

*1 represents a binding position to Z¹;

*2 represents a binding position to Z².

Examples of the groups represented by the formula (R²-1) and the groupsrepresented by the formula (R²-2) includes groups below. Here, *represents a binding position to W.

Among these, a group having the tertiary alkyl group is preferable, andtert-butyloxycarbonyl group is more preferable.

For R², a group represented by the formula (R²-1) in which R⁴, R⁵ and R⁶independently represent a C₁ to C₄ alkyl group is preferable, and agroup represented by the formula (R²-2) in which R⁷ and R⁸ independentlyrepresent a hydrogen atom or a C₁ to C₄ alkyl group is preferable, andalso, a group represented by the formula (R²-2) in which R⁹ representsany one of a group represented by any one of the formula (R⁹-1), theformula (R⁹-2), the formula (R⁹-3) and the formula (R⁹-4) is morepreferable. Among these, a hydrogen atom is preferable for R².

Further, n is preferably 1, and p is preferably 0 or 1.

As the compound represented by the formula (A), compounds represented bythe formula (A1) to the formula (A4) are preferable;

wherein R¹, R², R¹⁰, Z¹, Z², W, n and p represent the same meaning asdefined above; provided that n+p represents an integer of 1 to 3.

As the compound represented by the formula (A1), compound represented bythe formula (A1a) or the formula (A1b) below is preferable;

wherein R¹¹ represents a hydrogen atom, a hydroxy group or —OR¹⁰;

R¹, R² and R¹⁰ independently represent the same meaning as definedabove.

As the compound represented by the formula (A1), a compound representedby the formula (A1a1), the formula (A1a2), the formula (A1b1) or theformula (A1b2) below is more preferable;

wherein R¹, R² and R¹⁰ represent the same meaning as defined above.

In the compound represented by the formula (A1a1), the formula (A1a2),the formula (A1b1) or the formula (A1b2), a compound in which R¹ is ahydrogen atom or methyl group, and R² is a hydrogen atom is preferable.

Examples of the compound represented by the formula (A) includecompounds below.

The compound represented by the formula (A) can be produced, forexample, by a method described in schemes below.

A compound represented by the formula (3) can be obtained by reacting acompound represented by the formula (1) as a starting material, forexample, 3-hydroxy-1-adamantyl(meth)acrylate or3,5-dihydroxy-1-adamantyl(meth)acrylate with a compound represented bythe formula (2) such as chloroacetyl chloride in presence of a basiccatalyst in a solvent. Preferred examples of the basic catalyst includepyridine. Preferred examples of the solvent include tetrahydrofuran.

The compound represented by the formula (A-1) in which Z² is*—O—CO—(CH₂)_(k)—O—CO— can be obtained by reacting the obtained compoundrepresented by the formula (3) with a compound represented by theformula (4) such as benzoic acid in presence of a catalyst in a solvent.Preferred examples of the catalyst include a mixture of calciumcarbonate and potassium iodide. Preferred examples of the solventinclude N,N-dimethylformamide.

wherein R¹, R², Z¹, W and n represent the same meaning as defined above;

Z³ represents *—CO—(CH₂)_(k)—.

Also, the compound represented by the formula (A-2) in which Z² is*—O—CH₂—CO— can be obtained by replacing a hydrogen atom of methyl groupin a compound represented by the formula (5) such as 4-acetylphenol to ahalogen atom (preferably a bromine atom) in a solvent (preferablychloroform) to obtain a compound represented by the formula (6), andreacting the obtained compound represented by the formula (6) with acompound represented by the formula (7), for example,3-hydroxy-1-adamantyl(meth)acrylate or3,5-dihydroxy-1-adamantyl(meth)acrylate in presence of a catalyst in asolvent. Preferred examples of the catalyst include a mixture of calciumcarbonate and potassium iodide. Preferred examples of the solventinclude N,N-dimethylformamide.

wherein R¹, R², Z¹, W and n represent the same meaning as defined above;

X represents a halogen atom.

A resin of the present invention contains a structural unit derived fromthe compound represented by the formula (A). The resin may contain thecompound represented by the formula (A) singly or in combination withtwo or more. The resin of the present invention may be a resin havingthe structural unit derived from the compound represented by the formula(A) alone, and preferably a resin further contain a structural unitderived from a compound having an acid-labile group. Such resin isinsoluble or poorly soluble in aqueous alkali solution, and can dissolvein aqueous alkali solution by the action of acid.

The acid-labile group include —COOR group, examples of R includetert-butyl group, methoxymethyl, ethoxymethyl, 1-ethoxyethyl,1-isobutoxyethyl, 1-isopropoxyethyl, 1-ethoxypropyl,1-(2-methoxyethoxy)ethyl, 1-(2-acetoxyethoxy)ethyl,1-[2-(1-adamantyloxy)ethoxy]ethyl,1-[2-(1-adamantanecarbonyloxy)ethoxy]ethyl, tetrahydro-2-furyl,tetrahydro-2-pyranyl, isobornyl, 1-alkylcycloalkyl, 2-alkyl-2-adamantyland 1-(1-adamantyl)-1-alkylalkyl groups.

The resin of the present invention can be produced by conductingaddition polymerization reaction of a monomer or monomers having theacid-labile group and a carbon-carbon double bond.

Among the monomers, as the acid-labile group, those having a bulky groupsuch as an alicyclic structure (e.g. a 2-alkyl-2-adamantyl and a1-(1-adamantyl)-1-alkylalkyl groups) are preferable, since excellentresolution tends to be obtained when the resin obtained is used.

Examples of such monomer containing the bulky group include a2-alkyl-2-adamantyl(meth)acrylate,1-(1-adamantyl)-1-alkylalkyl(meth)acrylate, a 2-alkyl-2-adamantyl5-norbornene-2-carboxylate, a 1-(1-adamantyl)-1-alkylalkyl5-norbornene-2-carboxylate, a 2-alkyl-2-adamantyl α-chloroacrylate and a1-(1-adamantyl)-1-alkylalkyl α-chloroacrylate.

Particularly, the 2-alkyl-2-adamantyl(meth)acrylate or the2-alkyl-2-adamantyl α-chloroacrylate is preferably used as the monomersince the resist composition having excellent resolution tend to beobtained.

Specific examples of the 2-alkyl-2-adamantyl(meth)acrylate include2-methyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate,2-ethyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl methacrylate,2-n-butyl-2-adamantyl acrylate, 2-n-butyl-2-adamantyl methacrylate.Specific examples of the 2-alkyl-2-adamantyl α-chloro(meth)acrylateinclude 2-methyl-2-adamantyl α-chloroacrylate and 2-ethyl-2-adamantylα-chloroacrylate.

Among these, 2-ethyl-2-adamantyl(meth)acrylate or2-isopropyl-2-adamantyl(meth)acrylate is preferably because of theresist composition having excellent sensitivity and heat resistancetends to be obtained.

The 2-alkyl-2-adamantyl(meth)acrylate can be generally produced byreacting a 2-alkyl-2-adamantanol or a metal salt thereof with an acrylichalide or methacrylic halide.

In addition to structural units derived from compounds represented bythe formula (A) and structural units derived from monomers that haveacid-labile groups, the resin used in the present invention may includesstructural units derived from acid-stable monomers. Here, the structurederived from the acid-stable monomer means a structure that is notcleaved by the acid generator mentioned below.

Specific examples include;

a structural unit derived from a monomer such as acrylic acid andmethacrylic acid;

a structural unit derived from an aliphatic unsaturated dicarboxylicanhydride such as maleic anhydride and itaconic anhydride;

a structural unit derived from 2-norbornene;

a structural unit derived from (meth)acrylonitrile;

a structural unit derived from (meth)acrylic esters having —COO—CH(R′)₂or —COO—CH₂(R′), wherein R′ represents alkyl or 1-adamantyl group;

a structural unit derived from a styrene monomer such as p- orm-hydroxystyrene;

a structural unit derived from (meth)acryloyloxy-γ-butyrolactone havinga lactone ring which may be substituted with an alkyl group;

a structural unit derived from a monomer having 1-adamantyl group whichmay have a hydroxy group.

Specific examples of the acid-stable monomer include3-hydroxy-1-adamantyl(meth)acrylate,3,5-dihydroxy-1-adamantyl(meth)acrylate,α-(meth)acryloyloxy-γ-butyrolactone,β-(meth)acryloyloxy-γ-butyrolactone, a monomer giving a structural unitrepresented by the formula (a), a monomer giving a structural unitrepresented by the formula (b), p- or m-hydroxystyrene, 2-norbornene,maleic anhydride and itaconic anhydride.

Among these, the resist obtained from a resin having any of a structuralunit derived from the styrene monomer, a structural unit derived from3-hydroxy-1-adamantyl(meth)acrylate, a structural unit derived from3,5-dihydroxy-1-adamantyl(meth)acrylate, a structural unit representedby the formula (a), a structural unit represented by the formula (b) anda structural unit represented by the formula (f) is preferable becausethe adhesiveness of resist composition to a substrate and resolution ofresist composition tend to be improved.

wherein R²¹ and R²² independently represent a hydrogen atom or methylgroup;

R²³ and R²⁴ independently represent a hydrogen atom, methyl group,trifluoromethyl group or a halogen atom;

i and j represents an integer of 1 to 3.

Examples of the (meth)acryloyloxy-γ-butyrolactone includeα-acryloyoxy-γ-butyrolactone, α-methacryloxy-γ-butyrolactone,α-acryloyloxy-β-γ-butyrolactone, β-dimethyl-γ-butyrolactone,α-methacryloyloxy-β-γ-butyrolactone, β-dimethyl-γ-butyrolactone,α-acryloyloxy-α-methyl-γ-butyrolactone,α-methacryloyloxy-α-methyl-γ-butyrolactone,β-acryloyloxy-γ-butyrolactone, β-methacryloyloxy-γ-butyrolactone andβ-methacryloyloxy-α-meth-γ-butyrolactone.

When KrF excimer laser lithography and EUV or EB lithography are used,even in the case of using a structure unit derived from a styrenemonomer as the structure unit of the resin, the resist compositionhaving sufficient transparency can be obtained. Such resins can beobtained by radical-polymerizing the corresponding (meth)acrylic estermonomer with acetoxystyrene and styrene followed by de-acetylating themwith an acid.

Specific examples of the monomer giving the structural unit derived fromstyrene monomers include monomers below.

Among styrene monomers, 4-hydroxystyrene or 4-hydroxy-α-methylstyrene isparticular preferable.

The resin containing a structural unit derived from 2-norbornene showsstrong structure because the alicyclic group is directly present on itsmain chain and shows a property that dry etching resistance isexcellent. The structural unit derived from 2-norbornene can beintroduced into the main chain by radical polymerization using analiphatic unsaturated dicarboxylic anhydride such as maleic anhydrideand itaconic anhydride together in addition to corresponding2-norbornene. Therefore, the structural unit formed by opening of doublebond of norbornene can be represented by the formula (c), and thestructural unit formed by opening of double bond of maleic anhydride anditaconic anhydride can be represented by the formula (d) and (e),respectively.

wherein R²⁵ and R²⁶ in the formula (c) independently represent ahydrogen atom, a C₁ to C₃ alkyl group, a carboxyl group, a cyano groupor —COOU, or R²⁵ and R²⁶ are bonded together to form a group representedby —C(═O)OC(═O)—, one or more hydrogen atoms contained in the alkylgroup may be replaced by a hydroxy group.

U represents an optionally substituted C₁ to C₈ alkyl group or2-oxooxolan-3- or -4-yl group, the alkyl group may be substituted with ahydroxy group and an alicyclic hydrocarbon group.

Specific examples of the alkyl group include methyl, ethyl and propylgroups, and specific examples of the alkyl group having a hydroxy groupinclude hydroxymethyl and 2-hydroxyethyl groups.

Specific examples of monomer giving the structural unit represented bythe formula (c) include the following compounds;

-   2-norbornene,-   2-hydroxy-5-norbornene,-   5-norbornene-2-carboxylic acid,-   methyl 5-norbornene-2-carboxylate,-   2-hydroxy-1-ethyl 5-norbornene-2-carboxylate,-   5-norbornene-2-methanol, and-   5-norbornene-2,3-dicarboxylic acid anhydride.

The resin can contain a structural unit represented by the formula (f)as an acid-stable group.

wherein R³⁰ represents a hydrogen atom, a methyl group or atrifluoromethyl group;

AR represents a C₁ to C₃₀ hydrocarbon group, and at least one or morehydrogen atoms contained in the hydrocarbon group is replaced withfluorine atom, one or more —CH₂— contained in the hydrocarbon group maybe replaced by —O—, —S— or —N(R^(c))—, and a hydrogen atom contained inthe hydrocarbon group may be replaced by a hydroxy group or a C₁ to C₆alkyl group;

R^(c) represents a hydrogen atom or a C₁ to C₆ alkyl group.

Specific examples of the structural unit represented by the formula (f)include monomers below.

The content of the structural unit derived from the monomer having theacid-labile group in the resin may be generally adjusted to 10 to 80 mol% with respect to the total structural units constituting the resin.

When the structural unit derived from a2-alkyl-2-adamantyl(meth)acrylate or a1-(1-adamantyl)-1-alkylalkyl(meth)acrylate is included as the structuralunit derived from the monomer with the acid-labile group, adjusting thecontent to about 15 mol % or more with respect to the total structuralunits, which is advantageous in terms of the dry etching resistance ofthe resulting resist.

The weight average molecular weight of the resin is preferably 2500 to100,000, more preferably 2700 to 50000, and even more preferably 3000 to40000. The weight average molecular weight is a value determined by gelpermeation chromatography using polystyrene as the standard product. Thedetailed condition of this analysis is described in Examples.

The content of the structural unit derived from the compound representedby the formula (A) in the resin is preferably 5 to 95 weight %, and morepreferably 10 to 90 weight % with respect to the total structural unitsconstituting the resin.

Examples of the resin include a resin having structural unit of B1 tostructural unit of B 24 below.

A resist composition of the present invention includes the resindescribed above and an acid generator.

Examples of the acid generator include a diazonium salt, a phosphoniumsalt, a sulfonium salt, an iodonium salt, an imidosulfonate, anoximesulfonate, a diazodisulfone, a disulfone, ano-nitrobenzenesulfonate.

Also, examples include compounds described in U.S. Pat. No. 3,849,137-B,DE 3,914,407-B, JP-S63-26653-A, JP-S55-164824-A, JP-S62-69263-A,JP-S63-146038-A, JP-S63-163452-A, JP-S62-153853-A, JP-S63-146029 A, U.S.Pat. No. 3,779,778-B and EP 126,712-B as the acid generator.

An salt represented by the formula (I) is preferable for the acidgenerator.

wherein Q¹ and Q² independently represent a fluorine atom or a C₁ to C₆perfluoroalkyl group;

X² represents a single bond or a C₁ to C₂₁ divalent saturatedhydrocarbon group, one or more —CH₂— contained in the saturatedhydrocarbon group may be replaced by —O— or —CO— group;

Y¹ represents a C₁ to C₃₆ alkyl group or a C₃ to C₃₆ alicyclichydrocarbon group, and a C₃ to C₃₆ aromatic hydrocarbon group, and thealkyl group, the alicyclic hydrocarbon group and the aromatichydrocarbon group may be substituted, and one or more —CH₂-contained inthe alicyclic hydrocarbon group may be replaced by —O— or —CO— group;

Z⁺ represents an organic counter cation.

Examples of the fluoroalkyl group include perfluoromethyl,perfluoroethyl, perfluoro-n-propyl, perfluoro-isopropyl,perfluoro-n-butyl, perfluoro-sec-butyl, perfluoro-tert-butyl,perfluoro-n-pentyl and perfluoro-n-hexyl groups. Among these,perfluoromethyl group is preferable.

Examples of the divalent saturated hydrocarbon group include a groupincluding an alkylene group or a cycloalkylene group.

Examples of the alkylene group include methylene, dimethylene,trimethylene, tetramethylene, pentamethylene, hexamethylene,heptamethylene, octamethylene, nonamethylene, decamethylene,undecamethylene, dodecamethylene, tridecamethylene, tetradecamethylene,pentadecamethylene, hexadecamethylene, heptadecamethylene, ethylene,propylene, isopuropylene, sec-buthylene and tert-buthylene groups.

Examples of the cycloalkylene group include cyclopropylene,cyclobuthylene, cyclopenthylene, cyclohexylene, methyl cyclohexylene,dimethyl cyclohexylene, cycloheptylene and cyclooctylene groups.

For an anion of the salt represented by the formula (I) (herein afterpreferred to as “salt (I)”), Q¹ and Q² independently are preferablyperfluoromethyl or fluorine atom, and more preferably fluorine atom

Examples of the X² are suitably —CO—O—X¹⁰—, —CO—O—X¹¹—CO—O—, —X¹¹—O—CO—and —X¹¹—O—X¹²—, and preferably —CO—O—X¹⁰— and —CO—O—X¹¹—CO—O—.

X¹⁰, X¹¹ and X¹² independently represent a single bond or a C₁ to C₁₅alkylene group.

Y¹ is suitably a C₄ to C₃₆ alicyclic hydrocarbon group which may besubstituted.

Examples of the substituent of the optionally substituted the alkylgroup, the alicyclic hydrocarbon group and the aromatic hydrocarbongroup of Y¹ include a halogen atom, a hydroxy group, a C₁ to C₁₂ alkylgroup, a C₆ to C₂₀ aromatic hydrocarbon group, a C₇ to C₂₁ aralkylgroup, a glycidyloxy group and a C₂ to C₄ acyl group.

Examples of the anion of the salt represented by the formula (I) includethe following anions represented by the formulae (IA), (IB), (IC) and(ID). Among these, the anion represented by the formula (IA) and theformula (IB) are suitable.

Wherein Q¹, Q², Y¹ X¹⁰, X¹¹ and X¹² represent the same meaning asdefined above.

Examples of Y¹ include a group represented by the formula (W1) to theformula (W26). Among these, groups represented by the formula (W1) tothe formula (W19) are preferable, and groups represented by the formula(W12), (W15), (W16) and (W19) are more preferable.

Specific examples of Y¹ include the groups below.

Examples of the anion include the anions below.

Examples of the Z⁺ of the salt represented by the formula (I) includecations represented by the formula (IXz), the formula (IXb), the formula(IXc) and the formula (IXd).

wherein P^(a), P^(b) and P^(c) in the formula (IXz) independentlyrepresent a C₁ to C₃₀ alkyl group, a C₃ to C₃₀ alicyclic hydrocarbongroup or a C₆ to C₂₀ aromatic hydrocarbon group, one or more hydrogenatoms contained in the alkyl group may be replaced by a hydroxy group, aC₁ to C₁₂ alkyl group, a C₁ to C₁₂ alkoxy group or a C₃ to C₁₂ cyclichydrocarbon group, and one or more hydrogen atoms contained in thealicyclic hydrocarbon group or the aromatic hydrocarbon group may bereplaced by a halogen atom, a hydroxy group, a C₁ to C₁₂ alkyl group, aC₁ to C₁₂ alkoxy group or a C₄ to C₃₆ alicyclic hydrocarbon group;

P⁴ and P⁵ independently represent a hydrogen atom, a hydroxy group, a C₁to C₁₂ alkyl group or a C₁ to C₁₂ alkoxy group;

P⁶ and P⁷ independently represent a C₁ to C₁₂ alkyl group or a C₃ to C₁₂cycloalkyl group, or P⁶ and P⁷ may be bonded to form a C₃ to C₁₂ ring;

P⁸ represents a hydrogen atom;

P⁹ represents a C₆ to C₂₀ aromatic hydrocarbon group, or P⁸ and P⁹ maybe bonded to form a C₃ to C₁₂ ring, one or more hydrogen atoms containedin the aromatic hydrocarbon group may be replaced by a C₁ to C₁₂ alkylgroup or C₃ to C₁₂ cycloalkyl group;

P¹⁰ to P²¹ independently represent a hydrogen atom, a hydroxy group, aC₁ to C₁₂ alkyl group or a C₁ to C₁₂ alkoxy group;

E represents a sulfur atom or an oxygen atom; and

m represents 0 or 1.

Examples of the cyclic hydrocarbon group include any one of an alicyclichydrocarbon group and aromatic hydrocarbon group.

Among the cations represented by the formula (IXz), a cation representedby the formula (IXa) is preferable.

wherein P¹ to P³ independently represent a hydrogen atom, a hydroxygroup, a halogen atom, a C₁ to C₁₂ alkyl group, a C₁ to C₁₂ alkoxy groupor a C₄ to C₃₆ alicyclic hydrocarbon group, and one or more hydrogenatoms contained in the alicyclic hydrocarbon group may be replaced by ahalogen atom, a hydroxy group, a C₁ to C₁₂ alkyl group, a C₁ to C₁₂alkoxy group, a C₆ to C₁₂ aryl group, a C₇ to C₁₂ aralkyl group, aglycidyloxy group or a C₂ to C₄ acyl group.

Particularly, the alicyclic hydrocarbon group is suitably a groupcontaining adamantyl structure or isobornyl structure, and preferably2-alkyl-2-adamantyl group, 1-(1-adamantyl)-1-alkyl group and isobornylgroup.

Specific examples of the cation represented by the formula (IXa) includecations below.

Among the cation represented by the formula (IXa), a cation representedby the formula (IXe) is preferable because of easily-manufacturing.

wherein P²², P²³ and P²⁴ independently represent a hydrogen atom, ahydroxy group, a halogen atom, a C₁ to C₁₂ alkyl group or a C₁ to C₁₂alkoxy group.

Specific examples of the cation represented by the formula (IXb) includecations below.

Specific examples of the cation represented by the formula (IXc) includecations below.

Specific examples of the cation represented by the formula (IXd) includecations below.

The above-mentioned anions and cations can be combined as desired.

Examples of the salt represented by the formula (I) include thecompounds represented by the formula (Xa) to the formula (Xi).

wherein P²⁵, P²⁶ and P²⁷ independently represent a hydrogen atom, a C₁to C₄ alkyl group or a C₄ to C₃₆ alicyclic hydrocarbon group;

P²⁸ and P²⁹ independently represent a C₁ to C₁₂ alkyl group or a C₄ toC₃₆ alicyclic hydrocarbon group, or P²⁸ and P²⁹ can be bonded togetherto form a C₂ to C₆ ring that includes S⁺;

P³⁰ represent a C₁ to C₁₂ alkyl group, a C₄ to C₃₆ alicyclic hydrocarbongroup or an optionally substituted C₆ to C₂₀ aromatic hydrocarbon group,or P³⁰ and P³¹ can be bonded together to form a C₃ to C₁₂ ring, and oneor more —CH₂— contained in the ring may be replaced by —O—, —S— or —CO—;

Q¹ and Q² represent the same meaning as defined above and

X¹³ represents a single bond or a methylene group.

Examples of the ring formed by P²⁸ and P²⁹ bonded together includetetrahydrothiophenium group.

Examples of the ring formed by P³⁰ and P³¹ bonded together include thegroup represented by the formula (W13) to the formula (W15) describedabove.

Among the abovementioned combinations, examples include the salts below.

The salt represented by the formula (I) can be produced, for example,according to the manufacturing method described in JP-2008-209917-A.

In the resist composition of the present invention, the content of theacid generator is preferably in the range of 1 to 30 parts by weight,and more preferably 1 to 20 parts by weight, and still more preferably 1to 15 parts by weight with respect to 100 parts by weight of the resin.The acid generator represented by the formula (I) may be used singly orin combination with two or more.

The resist composition containing the acid generator and resin describedabove may include a basic compound. Preferred examples of the basiccompound include a nitrogen-containing organic compound, particularlyamines and ammonium salts. The basic compound can be added as a quencherto improve performance from being compromised by the inactivation of theacid while the material is standing after exposure.

The Examples of such basic compounds used as the quencher include thoserepresented by the following formulae.

wherein T¹, T² and T⁷ independently represent a hydrogen atom, a C₁ toC₆ alkyl group, a C₅ to C₁₀ alicyclic hydrocarbon group or a C₆ to C₂₀aromatic hydrocarbon group, one or more hydrogen atoms contained in thealkyl group, alicyclic hydrocarbon group and aromatic hydrocarbon groupmay be replaced by a hydroxy group, an amino group or a C₁ to C₆ alkoxygroup, one or more hydrogen atoms contained in the amino group may beplaced by a C₁ to C₄ alkyl group;

T³ to T⁵ independently represent a hydrogen atom, a C₁ to C₆ alkylgroup, a C₁ to C₆ alkoxy group, a C₅ to C₁₀ alicyclic hydrocarbon groupor a C₆ to C₂₀ aromatic hydrocarbon group, one or more hydrogen atomscontained in the alkyl group, the alkoxy group, the alicyclichydrocarbon group and aromatic hydrocarbon group may be replaced by ahydroxy group, an amino group or a C₁ to C₆ alkoxy group, one or morehydrogen atoms contained in the amino group may be replaced by a C₁ toC₄ alkyl;

T⁶ represents a C₁ to C₆ alkyl group or a C₅ to C₁₀ alicyclichydrocarbon group, one or more hydrogen atoms contained in the alkylgroup and the alicyclic hydrocarbon group may be replaced by a hydroxygroup, an amino group or a C₁ to C₆ alkoxy group, one or more hydrogenatoms contained in the amino group may be replaced by a C₁ to C₄ alkylgroup;

A represents a C₂ to C₆ alkylene group, a carbonyl group, an iminogroup, a sulfanediyl group or a disulfanediyl group.

Specific examples of such compounds include hexylamine, heptylamine,octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4-methylaniline,4-nitroaniline, diisopropylaniline, 1- or 2-naphtylamine,ethylenediamine, tetramethylenediamine, hexamethylenediamine,4,4′-diamino-1,2-diphenylethane,4,4′-diamino-3,3′-dimethyldiphenylmethane,4,4′-diamino-3,3′-diethyldiphenylmethane, dibutylamine, dipentylamine,dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine,N-methylaniline, piperidine, diphenylamine, triethylamine,trimethylamine, tripropylamine, tributylamine, tripentylamine,trihexylamine, triheptylamine, trioctylamine, trinonylamine,tridecylamine, methyldibutylamine, methyldipentylamine,methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine,methyldioctylamine, methyldinonylamine, methyldidecylamine,ethyldibutylamine, ethydipentylamine, ethyldihexylamine,ethydiheptylamine, ethyldioctylamine, ethyldinonylamine,ethyldidecylamine, dicyclohexylmethylamine,tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine,N,N-dimethylaniline, 2,6-diisopropylaniline, imidazole, pyridine,4-methylpyridine, 4-methylimidazole, bipyridine, 2,2′-dipyridylamine,di-2-pyridylketone, 1,2-di(2-pyridyl)ethane, 1,2-di(4-pyridyl)ethane,1,3-di(4-pyridyl)propane, 1,2-bis(2-pyridyl)ethylene,1,2-bis(4-pyridyl)ethylene, 1,2-bis(4-pyridyloxy)ethane,4,4′-dipyridylsulfide, 4,4′-dipyridyldisulfide,1,2-bis(4-pyridyl)ethylene, 2,2′-dipicolylamine, 3,3′-dipicolylamine,tetramethylammonium hydroxide, tetraisopropylammonium hydroxide,tetrabutylammonium hydroxide, tetra-n-hexylammonium hydroxide,tetra-n-octylammonium hydroxide, phenyltrimethylammonium hydroxide,3-(trifluoromethyl)phenyltrimethylammonium hydroxide, and(2-hydroxyethyl)trimethylammonium hydroxide (common name: choline).Among these, diisopropylaniline is preferable.

Furthermore, hindered amine compounds with a piperidine skeleton such asthose disclosed in JP-A-H11-52575 can be used as a quencher.

In the present resist composition, the content of the resin ispreferably in the range of about 80 to 99.9 wt %, and the content of theacid generator is preferably in the range of about 0.1 to 20 wt %, basedon the total amount of solids.

The content of the basic compound containing as a quencher in the resistcomposition, if used, is preferably in the range of about 0.01 to 1 wt%, based on the total amount of solids in the resist composition.

The resist composition can also include small amounts of variousadditives such as sensitizers, dissolution inhibitors, other resins,surfactants, stabilizers, and dyes, as needed.

The resist composition of the present invention is generally a resistsolution, with the various ingredients above dissolved in a solvent, andis applied onto a substrate such as a silicon wafer by a methodindustrially-used such as spin coating. The solvent used here can be anysolvent that is industrially used in the field and that dissolves theingredients, dries at a suitable rate, and results in a smooth, uniformfilm after evaporating off.

Examples thereof include glycol ether esters such as ethylcellosolveacetate, methylcellosolve acetate and propylene glycol monomethyl etheracetate; ethers such as diethylene glycol dimethyl ether; esters such asethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; ketonessuch as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone;and cyclic esters such as γ-butyrolactone. These solvents can be usedalone or in combination of two or more.

The method for producing a resist pattern of the present inventionincludes steps of:

(1) applying the resist composition of the present invention onto asubstrate;

(2) drying the applied composition to form a composition layer;

(3) exposing to the composition layer using a exposure device;

(4) baking the exposed composition layer and,

(5) developing the baked composition layer using a developing apparatus.

The application of the resist composition onto the substrate cangenerally be carried out through the use of a device such as a spincoater.

The drying, for example, can either be carried out by baking the appliedcomposition using a heating device such as a hotplate, or can be carriedout using a decompression device, and a composition layer is formed. Thetemperature in this case is generally the range of 50 to 200° C.Moreover, the pressure is generally the range of 1 to 1.0×10⁵ Pa.

The composition layer obtained is exposed to light using an exposuredevice or a liquid immersion exposure device. The exposure is generallycarried out through a mask that corresponds to the required pattern.Various types of exposure light source can be used, such as irradiationwith ultraviolet lasers such as KrF excimer laser (wavelength: 248 nm),ArF excimer laser (wavelength: 193 nm), F₂ laser (wavelength: 157 nm),or irradiation with far-ultraviolet wavelength-converted laser lightfrom a solid-state laser source (YAG or semiconductor laser or the like)or vacuum ultraviolet harmonic laser light or the like.

After exposure, the composition layer is subjected to a baking treatmentto promote the deprotection reaction. The baking temperature isgenerally in the range of 50 to 200° C., preferably in the range of 70to 150° C.

The composition layer is developed after the heat treatment, generallyby utilizing an alkaline developing solution using a developingapparatus. Here, for the alkaline developing solution, various types ofaqueous alkaline solutions used in this field can be satisfactory.Examples include aqueous solutions of tetramethylammonium hydroxide and(2-hydroxyethyl)trimethylammonium hydroxide (common name: choline).

After developing, it is preferable to rinse with ultrapure water and toremove any residual water on the substrate and the pattern.

The resin and composition using same of the present invention are usefulin resist compositions, and particularly in chemically amplifiedphotoresist compositions, and can be used in the microfabrication ofsemiconductors and in manufacture of liquid crystals, thermal printheads for circuit boards and the like, and furthermore in otherphotofabrication processes, and they can be suitably used in a widerange of applications. In particular, since they exhibit a superior LER,they can be used as a suitable chemically amplified photoresistcomposition for excimer laser lithography such as with KrF or the like,as well as EB lithography and EUV exposure lithography. Moreover, inaddition to liquid immersion exposure, they can also be used in dryexposure and the like. Furthermore, they can also be used in doubleimaging, and have industrial utility.

EXAMPLES

The resist composition of the present invention will be described morespecifically by way of examples, which are not construed to limit thescope of the present invention.

All percentages and parts expressing the content or amounts used in theExamples and Comparative Examples are based on weight, unless otherwisespecified.

The weight average molecular weight is a value determined by gelpermeation chromatography (Toso Co. ltd. HLC-8120GPC type, coulum: Threeof TSK gel Multipore HXL-M, solvent: tetrahydroflun) using polystyreneas the standard product.

Column: Three of TSK gel Multipore HXL-M+guardcolumn (Tosoh Co. Ltd.)

Eluant: tetrahydrofuran

Flow rate: 1.0 mL/min

Detecting device: RI detector

Column temperature: 40° C.

Injection amount: 100 μL

Standard material for calculating molecular weight: standardpolyethylene (Tosoh Co. Ltd.)

The structures of the compounds were verified by NMR (Nippon electric,GX-270 type or EX-270 type) and mass analysis (LC: Agilent 1100 type,MASS: Agilent LC/MSD type or LC/MSD TOF type).

Example 1 Synthesis of Compound (a1-4)

13.62 parts of a compound (a1-4-a) and 23.30 parts of 1,4-dioxane weremixed while stirring at 23° C. A mixture prepared by dissolving 25.00parts of bromine-dioxane complex in 125 parts of 1,4-dioxane was addedto the obtained mixed solution in the form of drops over 1 hour at 23°C. The obtained mixed solution was stirred for 1 hour at 23° C. To theobtained mixed solution were added 140 parts of 5% potassium carbonateaqueous solution and 115 parts of ethylacetate, and obtained solutionwas stirred and separated. To a recovered organic layer was added 133parts of ion-exchanged water to separate and wash, and then an organiclayer was recovered. The obtained organic layer was concentrated, thusconcentrated mass was mixed with 50 parts of methanol while stirring,and the recrystallization and filteration conducted, whereby giving17.80 parts of a compound (a1-4-b) as a white solid.

15.05 parts of compound (a1-4-b), 45.00 parts of ethylacetate and 0.0013parts of p-toluenesulfonic acid were mixed while stirring at 23° C. Tothe obtained mixed solution was added 6.06 parts of ethyl vinyl ether,the mixture was stirred for 5 hours at 23° C. To the obtained mixedsolution was added 33 parts of ion-exchanged water to separate and wash,and then an organic layer was recovered. The obtained organic layer wasconcentrated, whereby giving the compound (a1-4-b) in which hydroxygroup was protected.

10.00 parts of tetrahydrofuran (THF), 1.46 parts of4-dimethylaminopyridine and 2.36 parts of3-hydroxy-1-adamantyl-metacrylate were mixed while stirring at 23° C. Tothe obtained mixed solution was added 2.87 parts of the compound(a1-4-b) in which hydroxy group is protected for 1 hour at 40° C. Theobtained mixture solution was stirred for 16 hours at 40° C. To theobtained mixed solution were added 10.00 parts of ion-exchanged waterand 25.00 parts of ethyl acetate to separate and wash, and then anorganic layer was recovered. The obtained organic layer was mixed with25.0 parts of 5% potassium bicarbonate aqueous solution to separate andwash, and then an organic layer was recovered. To the obtained organiclayer was further added 25.00 parts of 1% hydrochloric acid, and theresultant mixture was stirred for 3 hours, and then an organic layer wasseparate and recovered. The obtained organic layer was concentrated, andthen column-fractionated under the condition below, whereby giving 1.58parts of the compound (a1-4).

Developing medium: silica gel 60, 200 mesh (Merck & Co., Inc.)

Developing solvent: n-heptane/ethyl acetate=10/1 (volume ratio)

MS: 370.2

¹H-NMR (dimethyl sulfoxide-d₆, internal standard materialtetramethylsilane): δ(ppm) 1.47-2.20 (m, 15H), 2.31-2.40 (m, 2H), 4.67(s, 2H), 5.49 (m, 1H), 6.01 (m, 1H), 7.78 (m, 2H), 7.85 (m, 2H), 9.59(s, 1H)

Example 2 Synthesis of Compound (a1-5)

0.42 parts of a compound (a1-5) was produced in the same manner as inExample 1 except that 2.52 parts of 3,5-dihydroxy-1-adamantylmethacrylate was used instead of 2.36 parts of 3-hydroxy-1-adamantylmethacrylate.

MS: 386.2

¹H-NMR (dimethyl sulfoxide-d₆, internal standard materialtetramethylsilane): δ(ppm) 1.89 (s, 3H), 1.95-2.15 (m, 6H), 2.35-2.62(m, 7H), 4.42 (bs, 1H), 4.67 (s, 2H), 5.49 (m, 1H), 6.01 (m, 1H), 7.78(m, 2H), 7.85 (m, 2H), 9.59 (s, 1H)

Example 3 Synthesis of Compound (a1-4′)

23.63 parts of 3-hydroxy-1-adamantyl methacrylate and 100 parts of THFwere mixed while stirring 1 hour at 23° C. To the obtained mixedsolution was added 10.49 parts of 4-dimethylaminopyridine, and themixture was heated up to 40° C. A mixed solution containing 16.94 partsof chloroacetyl chloride and 34 parts of THF was added thereto in theform of drops over 1 hour. After that, the obtained mixture was stirredfor 8 hours at 40° C., and cooled down to 5° C. 100 parts ofion-exchanged water of 5° C. was added thereto, and the obtained mixturewas stirred and separated to recover a water layer. To the obtainedwater layer was added 300 parts of ethyl acetate, and separated torecover an organic layer. To the obtained organic layer was added 200parts of 10% potassium carbonate aqueous solution of 5° C. to wash, andseparated to recover an organic layer. Then, to the recovered organiclayer was added 200 parts of ion-exchanged water to wash, and theresultant was separated to recover an organic layer. These operationswere repeated 3 times, and the recovered organic layer was concentrated,whereby giving 10.69 parts of a compound (a1-4′-b).

1.38 parts of 4-hydroxy-benzoic acid and 20 parts ofN,N-dimethylformamide (DMF) were mixed while stirring 1 hour at 23° C.To the obtained mixed solution were added 0.69 parts of potassiumcarbonate and 0.17 parts of potassium iodide, and the mixture was heatedup to 50° C. The resultant mixture was stirred for 1 hour, and heated upto 100° C. To the obtained mixture was added in the form of drops amixed solution containing 3.13 parts of the compound (a1-4′-b) and 30parts of DMF over 1 hour, the resultant mixture was stirred 3 hours at100° C. The obtained mixture was cooled to 23° C., and 50 parts ofion-exchanged water and 200 parts of ethyl acetate were added thereto,and the obtained mixture was stirred and separated to recover an organiclayer. To the obtained organic layer was added 50 parts of 5% potassiumcarbonate aqueous solution of 5° C. to wash, and separated to recover anorganic layer. Then, to the recovered organic layer was added 100 partsof ion-exchanged water to wash, and the resultant was separated torecover an organic layer. These operations were repeated 3 times, andthe recovered organic layer was concentrated, and thencolumn-fractionated under the condition below, whereby giving 1.26 partsof the compound (a1-4′).

Developing medium: silica gel 60, 200 mesh (Merck & Co., Inc.)

Developing solvent: n-heptane/ethyl acetate=10/1 (volume ratio)

MS: 414.2

¹H-NMR (dimethyl sulfoxide-d₆, internal standard materialtetramethylsilane): δ(ppm) 1.47-2.20 (m, 15H), 2.31-2.40 (m, 2H), 5.25(s, 2H), 5.49 (m, 1H), 6.01 (m, 1H), 7.78 (m, 2H), 7.95 (m, 2H), 9.59(s, 1H)

Example 4 Synthesis of Compound (a1-5′)

0.43 parts of a compound (a1-5′) was produced in the same manner as inExample 3 except that 25.23 parts of 3,5-dihydroxy-1-adamantylmethacrylate was used instead of 2.36 parts of 3-hydroxy-1-adamantylmethacrylate.

MS: 430.2

¹H-NMR (dimethyl sulfoxide-d₆, internal standard materialtetramethylsilane): δ(ppm) 1.89 (s, 3H), 1.95-2.15 (m, 6H), 2.35-2.62(m, 7H), 4.42 (bs, 1H), 5.25 (s, 2H), 5.49 (m, 1H), 6.01 (m, 1H), 7.78(m, 2H), 7.85 (m, 2H), 9.59 (s, 1H)

Example 5 Synthesis of Compound (a1-A)

0.86 parts of a compound (a1-A) was produced in the same manner as inExample 3 except that 3-hydroxy-benzoic acid was used instead of4-hydroxy-benzoic acid and.

MS: 414.2

Example 6 Synthesis of Compound (a1-B)

2.59 parts of sodium hydride and 15.00 parts of THF were mixed, and themixture was stirred for 30 minutes at 0° C. To the obtained mixture wasadded a mixed solution containing 11.00 parts of the compound (a1-4) and40.00 parts of THF for 2 hours at 0° C., and the obtained mixture wasstirred for 1 hour at 0° C. To the obtained mixture was added 3.81 partsof methoxymethyl chloride for 40 minutes at 0° C., and stirred for 2hours at 0° C. 55 parts of ion-exchanged water and 220 part of ethylacetate were added thereto, and thus obtained mixture was separated torecover an organic layer. To the obtained organic layer was added 55parts of ion-exchanged water, and separated to recover an organic layer.The recovered organic layer was concentrated, and thencolumn-fractionated under the condition below, whereby giving 6.84 partsof the compound (a1-B).

Developing medium: silica gel 60, 200 mesh (Merck & Co., Inc.)

Developing solvent: n-heptane/ethyl acetate=4/1 (volume ratio)

MS: 414.2

Example 7 Synthesis of Compound (a1-C)

4.97 parts of sodium hydride and 15.00 parts of THF were mixed and themixture was stirred for 30 minutes at 0° C. To the obtained mixture wereadded a mixed solution containing 11.00 parts of the compound (a1-5) and40.00 parts of THF for 2 hours at 0° C., and the obtained mixture wasstirred for 1 hour at 0° C. To the obtained mixture was added 7.31 partsof methoxymethyl chloride for 40 minutes 0° C., and stirred for 2 hoursat 0° C. 55 parts of ion-exchanged water and 220 parts of ethyl acetatewere added thereto, and thus obtained mixture was separated to recoveran organic layer. To the obtained organic layer was added 55 parts ofion-exchanged water, and separated to recover an organic layer. Therecovered organic layer was concentrated, and then column-fractionatedunder the condition below, whereby giving 3.72 parts of the compound(a1-C).

Developing medium: silica gel 60, 200 mesh (Merck & Co., Inc.)

Developing solvent: n-heptane/ethylacetate=1/1 (volume ratio)

MS: 474.2

Example 8 Synthesis of Compound (a1-D)

4.41 parts of the compound (a1-4), 30.83 parts of THF and 2.18 parts of4-dimethylaminopyridine were mixed and the mixture was stirred for 30minutes at 23° C. To the obtained mixture was added 3.37 parts ofdi-tert-butyldicarbonate in the form of drops, and the obtained mixturewas stirred for 5 hour at 40° C. To the obtained mixture was added 1.81parts of conc. hydrochloric acid, and the resultant mixture was stirredfor 30 minutes. Then, 40 parts of ethyl acetate was added thereto, andthe mixture was stirred and thus obtained mixture was separated torecover an organic layer. To the obtained organic layer was added 10parts of ion-exchanged water to wash, and separated to recover anorganic layer. The recovered organic layer was concentrated, and thencolumn-fractionated under the condition below, whereby giving 1.46 partsof the compound (a1-D).

Developing medium: silica gel 60, 200 mesh (Merck & Co., Inc.)

Developing solvent: n-heptane/ethyl acetate=1/1 (volume ratio)

MS: 470.2

Example 9 Synthesis of Compound (a1-E)

0.28 parts of a compound (a1-E) was produced in the same manner as inExample 3 except that 3.45 parts of 4-hydroxy-benzoic acid, 1.73 partsof potassium carbonate and 0.42 parts of potassium iodide were usedinstead of 1.38 parts of 4-hydroxy-benzoic acid, 0.69 parts of potassiumcarbonate and 0.17 parts of potassium iodide.

Example 10 Synthesis of Resin (B1)

2-ethyl-2-adamantyl methacrylate and the compound (a1-4) were mixed withmolar ratio 25:75, and dioxane was added thereto in an amount equal to1.5 weight times of the total amount of monomers to obtain a solution.Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were addedas initiators thereto in an amount of 1 mol % and 3 mol % respectivelywith respect to the entire amount of monomers, and the resultant mixturewas heated for about 5 hours at 75° C. After that, the reaction solutionwas poured into a mixture methanol and ion-exchanged water in largeamounts to precipitate. These operations were repeated 3 times forpurification, whereby giving 65% yield of copolymer having a weightaverage molecular weight of about 7900. This copolymer was designatedResin B1.

Example 11 Synthesis of Resin (B2)

2-ethyl-2-adamantyl methacrylate and the compound (a1-5) were mixed withmolar ratio 25:75, and dioxane was added thereto in an amount equal to1.5 weight times of the total amount of monomers to obtain a solution.Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were addedas initiators thereto in an amount of 1 mol % and 3 mol % respectivelywith respect to the entire amount of monomers, and the resultant mixturewas heated for about 5 hours at 75° C. After that, the reaction solutionwas poured into a mixture methanol and ion-exchanged water in largeamounts to precipitate. These operations were repeated 3 times forpurification, whereby giving 64% yield of copolymer having a weightaverage molecular weight of about 7800. This copolymer was designatedResin B2.

Example 12 Synthesis of Resin (B3)

2-ethyl-2-adamantyl methacrylate and the compound (a1-4′) were mixedwith molar ratio 25:75, and dioxane was added thereto in an amount equalto 1.5 weight times of the total amount of monomers to obtain asolution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)were added as initiators thereto in an amount of 1 mol % and 3 mol %respectively with respect to the entire amount of monomers, and theresultant mixture was heated for about 5 hours at 75° C. After that, thereaction solution was poured into a mixture methanol and ion-exchangedwater in large amounts to precipitate. These operations were repeated 3times for purification, whereby giving 60% yield of copolymer having aweight average molecular weight of about 7600. This copolymer wasdesignated Resin B3.

Example 13 Synthesis of Resin (B4)

2-ethyl-2-adamantyl methacrylate and the compound (a1-5′) were mixedwith molar ratio 25:75, and dioxane was added thereto in an amount equalto 1.5 weight times of the total amount of monomers to obtain asolution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)were added as initiators thereto in an amount of 1 mol % and 3 mol %respectively with respect to the entire amount of monomers, and theresultant mixture was heated for about 5 hours at 75° C. After that, thereaction solution was poured into a mixture methanol and ion-exchangedwater in large amounts to precipitate. These operations were repeated 3times for purification, whereby giving 59% yield of copolymer having aweight average molecular weight of about 7300. This copolymer wasdesignated Resin B4.

Example 14 Synthesis of Resin (B5)

2-ethyl-2-adamantyl methacrylate and the compound (a1-A) were mixed withmolar ratio 25:75, and dioxane was added thereto in an amount equal to1.5 weight times of the total amount of monomers to obtain a solution.Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were addedas initiators thereto in an amount of 1 mol % and 3 mol % respectivelywith respect to the entire amount of monomers, and the resultant mixturewas heated for about 5 hours at 75° C. After that, the reaction solutionwas poured into a mixture methanol and ion-exchanged water in largeamounts to precipitate. These operations were repeated 3 times forpurification, whereby giving 52% yield of copolymer having a weightaverage molecular weight of about 7000. This copolymer was designatedResin B5.

Example 15 Synthesis of Resin (B6)

2-ethyl-2-adamantyl methacrylate and the compound (a1-B) were mixed withmolar ratio 25:75, and dioxane was added thereto in an amount equal to1.5 weight times of the total amount of monomers to obtain a solution.Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were addedas initiators thereto in an amount of 1.2 mol % and 3.6 mol %respectively with respect to the entire amount of monomers, and theresultant mixture was heated for about 5 hours at 75° C. After that, thereaction solution was poured into a mixture methanol and ion-exchangedwater in large amounts to precipitate. These operations were repeated 3times for purification, whereby giving 55% yield of copolymer having aweight average molecular weight of about 5900. This copolymer wasdesignated Resin B6.

Example 16 Synthesis of Resin (B7)

2-ethyl-2-adamantyl methacrylate and the compound (a1-C) were mixed withmolar ratio 25:75, and dioxane was added thereto in an amount equal to1.5 weight times of the total amount of monomers to obtain a solution.Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were addedas initiators thereto in an amount of 1.5 mol % and 4.5 mol %respectively with respect to the entire amount of monomers, and theresultant mixture was heated for about 5 hours at 75° C. After that, thereaction solution was poured into a mixture methanol and ion-exchangedwater in large amounts to precipitate. These operations were repeated 3times for purification, whereby giving 48% yield of copolymer having aweight average molecular weight of about 4800. This copolymer wasdesignated Resin B7.

Example 17 Synthesis of Resin (B8)

2-ethyl-2-adamantyl methacrylate and the compound (a1-D) were mixed withmolar ratio 25:75, and dioxane was added thereto in an amount equal to1.5 weight times of the total amount of monomers to obtain a solution.Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were addedas initiators thereto in an amount of 1.2 mol % and 3.6 mol %respectively with respect to the entire amount of monomers, and theresultant mixture was heated for about 5 hours at 75° C. After that, thereaction solution was poured into a mixture methanol and ion-exchangedwater in large amounts to precipitate. These operations were repeated 3times for purification, whereby giving 48% yield of copolymer having aweight average molecular weight of about 5600. This copolymer wasdesignated Resin B8.

Example 18 Synthesis of Resin (B9)

2-ethyl-2-adamantyl methacrylate and the compound (a1-E) were mixed withmolar ratio 25:75, and dioxane was added thereto in an amount equal to1.5 weight times of the total amount of monomers to obtain a solution.Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were addedas initiators thereto in an amount of 1.2 mol % and 3.6 mol %respectively with respect to the entire amount of monomers, and theresultant mixture was heated for about 5 hours at 75° C. After that, thereaction solution was poured into a mixture methanol and ion-exchangedwater in large amounts to precipitate. These operations were repeated 3times for purification, whereby giving 44% yield of copolymer having aweight average molecular weight of about 5500. This copolymer wasdesignated Resin B9.

Synthesis of Resin (Z1)

39.7 g (0.16 mole) of 2-ethyl-2-adamantyl methacrylate and 103.8 g (0.64mole) of p-acetoxystyrene were dissolved in 265 g isopropanol, and theobtained solution was elevated the temperature to 75° C. under anatmosphere of nitrogen. A solution in which 11.05 g (0.048 mole) ofdimethyl 2,2-azobis(2-methylpropionate) as a radical initiator wasdissolved in 22.11 g of isopropanol was added in the form of dropsthereto. The reacted solution was heated to reflux for 12 hours, cooledand pored into methanol in the large amounts to precipitate a polymer.The precipitate was filtrated, whereby giving 250 g of a copolymer of2-ethyl-2-adamantyl methacrylate and p-acetoxystyrene (containingmethanol).

250 g of thus obtained copolymer and 10.3 g (0.084 mole) of4-dimethylaminopyridine were added to 202 g of methanol, and the mixturewas heated to reflux for 20 hours, cooled, neutralized with 7.6 g (0.126mole) of glacial acetic acid, and pored into a water in the largeamounts to precipitate. The precipitate was filtrated, and dissolvedinto acetone. The obtained solution was pored into a water in the largeamounts, these operations were repeated 3 times for purification,whereby giving 95.9 g of a copolymer of 2-ethyl-2-adamantyl methacrylateand p-hydroxystyrene, having a weight average molecular weight of about8600 (GPC polystyrene conversion) and a copolymer ratio of about 20:80This copolymer was designated Resin Z1.

Synthesis of Resin (Z2)

102.8 g of a copolymer of 2-ethyl-2-adamantyl methacrylate andp-hydroxystyrene, having a weight average molecular weight of about 8200(GPC polystyrene conversion) and a copolymer ratio of about 30:70 (C¹³NMR measurement) was produced in the same manner as in Synthesis ofResin (Z1) except that 59.6 g (0.24 mole) of 2-ethyl-2-adamantylmethacrylate and 90.8 g (0.56 mole) of p-acetoxystyrene was used. Thiscopolymer was designated Resin Z2.

Examples and Comparative Examples

The resist compositions were prepared by mixing and dissolving each ofthe components shown in Table 1, and then filtering through afluororesin filter having 0.2 μm pore diameter.

TABLE 1 Resin Acid generator Quencher PB/PEB (parts) (parts) (parts) (°C.) Ex. 19 B1 = 10 A1 = 1.50 Q1/Q2 = 0.03/0.03 110/110 Ex. 20 B2 = 10 A1= 1.50 Q1/Q2 = 0.03/0.03 110/110 Ex. 21 B3 = 10 A1 = 1.50 Q1/Q2 =0.03/0.03 110/110 Ex. 22 B4 = 10 A1 = 1.50 Q1/Q2 = 0.03/0.03 110/110 Ex.23 B5 = 10 A1 = 1.50 Q1/Q2 = 0.03/0.03 110/110 Ex. 24 B6 = 10 A1 = 1.50Q1/Q2 = 0.03/0.03 110/110 Ex. 25 B7 = 10 A1 = 1.50 Q1/Q2 = 0.03/0.03110/110 Ex. 26 B8 = 10 A1 = 1.50 Q1/Q2 = 0.03/0.03 110/110 Ex. 27 B9 =10 A1 = 1.50 Q1/Q2 = 0.03/0.03 110/110 Ex. 28 B2 = 13.5 A2/A3 = 0.45/0.6Q1 = 0.049 110/110 Comp. Ex. 1 Z1/Z2 = 6.75/6.75 A2/A3 = 0.45/0.6 Q1 =0.049 110/110

<Acid Generator>

Acid Generator A1:

Acid Generator A2:

-   triphenylsulfonium 2,4,6-triisopropylbenzenesulfonate

Acid Generator A3:

-   bis(cyclohexylsulfonium)diazomethane

<Basic compound: Qencher>

-   Q1: 2,6-diisopropylaniline,-   Q2: tetrabutylammonium hydroxide

<Solvent of Resist Composition>

Propylene glycol monomethyl ether acetate 400 parts Propylene glycolmonomethyl ether 100 parts γ-butyrolactone  5 parts[Evaluation of Resist Composition for Electron-Beam Lithography]

Silicon wafers were treated using hexamethyldisilazane for 60 sec on adirect hot plate at 90° C.

The above resist liquids were then applied thereon by spin coating sothat the thickness of the resulting film became 0.06 μm after drying.

The obtained wafers were then pre-baked for 60 sec on a direct hot plateat the temperatures given in the “PB” column in Table 1.

Line and space patterns were then exposed through stepwise changes inexposure quantity using an electron beam lithography system (“HL-800D 50keV” by Hitachi), on the wafers on which the resist film had thus beenformed.

The exposure was followed by 60 seconds of post-exposure baking at thetemperatures given in the “PEB” column in Table 1.

This was followed by 60 sec of puddle development with 2.38 wt %tetramethylammonium hydroxide aqueous solution.

Table 2 gives the results of scanning electron microscopy of thedeveloped pattern on the silicon substrate.

Line edge roughness (LER) evaluation: when the wall surface of theresist pattern following the lithography process in which the exposureamount was set so as to resolved a 100 nm line and space pattern to 1:1,was observed using a scanning electron microscope, a OO was given if thedifference between the highest part and the lowest part on the resistpattern side wall (i.e., difference in height of the asperity on theside wall of the resist pattern) was ≦7 nm, a O was given if thedifference on the resist pattern side wall was >7 nm and ≦8 nm, and itreceived an X if these are >8 nm. In the Table 2, numerical valuesrepresents measurement results (unit: nm).

TABLE 2 LER Ex. 19 ∘∘ (6.8) Ex. 20 ∘∘ (6.4) Ex. 21 ∘∘ (6.7) Ex. 22 ∘∘(6.4) Ex. 23 ∘ (7.3) Ex. 24 ∘ (7.0) Ex. 25 ∘ (7.2) Ex. 26 ∘ (7.8) Ex. 27∘∘ (7.0) Ex. 28 ∘ (8.0) Comp. Ex. 1 x (8.5)[Evaluation of Resist Composition for EUV Lithography]

Silicon wafers were treated using hexamethyldisilazane for 60 sec on adirect hot plate at 90° C.

The above resist liquids were then applied thereon by spin coating sothat the thickness of the resulting film became 50 nm after drying.

The obtained wafers were then pre-baked for 60 sec on a direct hot plateat the temperatures given in the “PB” column in Table 1

Line and space patterns were then exposed through stepwise changes inexposure quantity using an EUV stepper on the wafers on which the resistfilm had thus been formed.

The exposure was followed by 60 seconds of post-exposure baking at thetemperatures given in the “PEB” column in Table 1

This was followed by 60 sec of puddle development with 2.38 wt %tetramethylammonium hydroxide aqueous solution.

Table 3 gives the results of scanning electron microscopy of thedeveloped pattern on the silicon substrate.

Line edge roughness (LER) evaluation: when the wall surface of theresist pattern following the lithography process in which the exposureamount was set so as to resolved a 50 nm line and space pattern to 1:1was observed using a scanning electron microscope, a OO was given if thedifference between the highest part and the lowest part on the resistpattern side wall was ≦5 nm, a O was given if the difference on theresist pattern side wall was >5 nm and ≦7 nm, and it received an X ifthese are >7 nm. In the Table 3, numerical values represents measurementresults (unit: nm).

Table 3 gives the there results.

TABLE 3 LER Ex. 19 ∘ (5.4) Ex. 20 ∘∘ (4.9) Ex. 21 ∘ (5.4) Ex. 22 ∘∘(4.8) Comp. Ex. 1 x (7.2)

According to the compound and the resist composition containing a resinwhich has a structural unit derived from the compound of the presentinvention, it is possible to achieve satisfactory pattern line edgeroughness in the pattern formed.

This application claims priority to Japanese Patent Application No. JP2009-202725. The entire disclosure of Japanese Patent Application No. JP2009-202725 is hereby incorporated herein by reference.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents. Thus, the scope ofthe invention is not limited to the disclosed embodiments.

What is claimed is:
 1. A compound represented by the formula (A);

wherein R¹ represents a hydrogen atom or a C₁ to C₆ alkyl group; Z¹represents —CO—O—* or —CO—O—(CH₂)_(k)—CO—O—*; Z² represents a singlebond, *—O—CO—, *—CO—O—, *—O—(CH₂)_(k)—CO—, *—CO—(CH₂)_(k)—O—,*—O—(CH₂)_(k)—CO—O—, *—O—CO—(CH₂)_(k)—O— or *—O—CO—(CH₂)_(k)—O—CO—; krepresents an integer of 1 to 6; * represents a binding position to W; Wrepresents a C₄ to C₃₆ (n+1) valent alicyclic hydrocarbon group, one ormore hydrogen atoms contained in the alicyclic hydrocarbon group may bereplaced by a halogen atom, a C₁ to C₁₂ alkyl group, a C₁ to C₁₂ alkoxygroup, a C₂ to C₄ acyl group or —OR¹⁰; R¹⁰ represents a hydrogen atom ora group represented by the formula (R²-2); R² represents a hydrogenatom, a group represented by the formula (R²-1) or a group representedby the formula (R²-2); n represents an integer of 1 to 3;

wherein R⁴, R⁵ and R⁶ independently represent a C₁ to C₁₂ hydrocarbongroup;

wherein R⁷ and R⁸ independently represent a hydrogen atom or a C₁ to C₁₂hydrocarbon group; R⁹ represents a C₁ to C₁₄ hydrocarbon group.
 2. Thecompound according to claim 1, wherein the compound represented by theformula (A) is a compound represented by the formula (A1);

wherein R¹, R², R¹⁰, Z¹, Z² and n represent the same meaning as definedin claim 1, p represents an integer of 0 to 3, provided that n+p is aninteger of 1 to
 3. 3. The compound according to claim 1, wherein the Z¹is —CO—O—*.
 4. The compound according to claim 1, wherein the Z² is*—O—(CH₂)_(k)—CO or *—O—CO—(CH₂)_(k)—O—CO—, wherein k represents thesame meaning as defined in claim
 1. 5. The compound according to claim1, wherein the n represents
 1. 6. A resin comprising a structural unitderived from the compound of the claim
 1. 7. The resin according toclaim 6, which further comprising an acid-labile group, and beinginsoluble or poorly soluble in aqueous alkali solution but becomingsoluble in aqueous alkali solution by the action of acid.
 8. A resistcomposition comprising a resin according to claim 6, and an acidgenerator.
 9. The resist composition according to claim 8, which furthercomprises a basic compound.
 10. A method for producing a resist patterncomprising steps of; (1) applying the resist composition according toclaim 8 or 9 onto a substrate; (2) drying the applied composition toform an composition layer; (3) exposing the composition layer using anexposure device; (4) baking the exposed composition layer and, (5)developing the baked composition layer using a developing apparatus,wherein in step (3), the composition layer is exposed to light and instep (5), the composition is developed utilizing an alkaline developingsolution.